UNIT 1 Flashcards
What is the difference between a somatic cell and a germline cell?
somatic is any cell in the body other than cells involved in reproduction, its diploid
Germline cell are gametes and the stem cell that divides to form gametes. its haploid
What is the difference between haploid and diploid chromosome complement?
Haploid cells have 23 single chromosomes (one set of chromosomes) , while diploid cells have 23 pairs of homologous chromosomes.(2 sets of chromosome = 46 single)
What type of cell division is carried out by a somatic stem cell ?
Mitosis to produce more somatic cells.
What type of cell division is carried out by a Germline stem cell ?
-Divide by mitosis to produce more germline stem cells.
- Divide by meiosis to produce haploid gametes
Describe the process of meiosis.
Meiosis involves two divisions :
1- first separate homologous chromosomes and
2- then separate chromatids.
Describe the process of differentiation.
Differentiation is the process by which a cell expresses certain genes to produce proteins characteristic of that cell type, allowing it to carry out specialized functions.
Why are cells of the very early embryo described as pluripotent?
Cells in the very early embryo are pluripotent, meaning they can differentiate into all the cell types that make up the individual.
What is the role of tissue stem cells?
Tissue stem cells are involved in the growth, repair, and renewal of the cells found in that tissue.
Why are tissue stem cells described as multipotent, and give an example?
Tissue stem cells are multipotent, meaning they can differentiate into all the cell types found in a particular tissue.
such as blood stem cells located in bone marrow producing red blood cells, platelets, and lymphocytes.
Describe therapeutic and research uses of stem cells.
Stem cells have therapeutic uses in repairing damaged or diseased organs,
and research uses in studying disease development and drug testing.
What are possible ethical issues of using embryonic stem cells?
the use of embryonic stem cells can offer effective treatment for injuries however it involves the destruction oif embryos.
Describe how cancer cells form , develop and spread throughout the body?
Cancer cells divide excessively as they don’t respond to regulatory signals .
this leads to a mass of abnormal cells known as tumour.
The cells within the tumour may fail to attach and spread throughout the body forming a secondary tumour.
Describe the structure of DNA.
DNA is two strands twisted to form a double helix
Identify the parts of a DNA nucleotide.
A DNA nucleotide is made up of a phosphate, deoxyribose sugar, and one of the four DNA bases.
Name the component which is found at the 3’ end and at the 5’ end of a nucleotide.
The deoxyribose sugar is found at the 3’ end,
the phosphate is found at the 5’ end of a nucleotide.
Explain how DNA nucleotides join to form a strand of DNA.
The nucleotides bond the sugar to the phosphate to form the sugar-phosphate backbone of the DNA strand.
Explain why the DNA strands are described as antiparallel.
The DNA strands run at the opposite direction
State the base pairing rule between the DNA bases.
Adenine pairs with thymine, and guanine pairs with cytosine.
Name the type of bond which forms between DNA bases.
Hydrogen bonds
State when DNA replication occurs.
DNA is replicated prior to cell division.
Name the enzyme that replicates DNA.
DNA Polymerase
Describe the structure and function of a primer.
A primer is a short strand of nucleotides that binds to the 3’ end of the template DNA strand,
allowing DNA polymerase to add new DNA nucleotides.
Describe how DNA unwinds and unzips to form two template strands.
Prior to replication, the DNA double helix is unwound and the hydrogen bonds between the bases are broken, forming two template strands.
Name the end of the new DNA molecule which DNA polymerase adds nucleotides to.
DNA polymerase adds nucleotides to the 3’ end of the new DNA strand.
Explain why the leading strand is replicated continuously and the lagging strand is replicated in fragments.
because DNA polymerase can only add nucleotides in the 5’ to 3’ direction.
Name the enzyme which joins the fragments of the lagging strand.
DNA Ligase
Describe the role of the polymerase chain reaction (PCR).
PCR amplifies DNA using complementary primers for specific target sequences.
Describe the structure and function of a primer used in PCR.
primers are short strands of nucleotides that are complementary to specific target sequences at the two ends of the region of DNA to be amplified.
Describe the process of PCR?
1- DNA is heated to between 92°C and 98°C to separate the strands
2- It is then cooled to between 50°C and 65°C to allow primers to bind to specific target sequences.
3- It is then heated to between 70°C and 80°C for heat tolerance DNA polymerase to replicate the target region of DNA
Give examples of practical applications of PCR.
PCR can be used to amplify DNA to help solve crimes, settle paternity suits, and diagnose genetic disorders.
Explain how macromolecules, such as DNA fragments, can be separated using electrophoresis.
as DNA is negatively charged and is attracted towards a positive charge, with the smaller fragments traveling further in the gel.
Describe the structure of RNA.
RNA is single-stranded and composed of nucleotides containing ribose sugar, phosphate, and one of four bases.
Compare the structure of RNA to the structure of DNA.
DNA is double-stranded and contains deoxyribose sugar and thymine, while RNA is single-stranded and contains ribose sugar and uracil.
Describe the role of mRNA.
Messenger RNA (mRNA) carries a copy of the DNA code from the nucleus to the ribosome for protein synthesis.
State the term used to describe each triplet of bases on mRNA.
Each triplet of bases on mRNA is called a codon and codes for a specific amino acid.
Describe the role of tRNA.
Transfer RNA (tRNA) carries its specific amino acid to the ribosome.
Describe the structure of tRNA.
tRNA has an anticodon (triplet of bases) at one end and an attachment site for an amino acid at the other end.
State the term used to describe each triplet of bases on tRNA.
an anticodon.
Describe how ribosomes are formed.
Ribosomal RNA (rRNA) combines with proteins to form the ribosome.
State the location of transcription within a cell.
Nucleus
Describe how RNA polymerase synthesises a primary transcript of mRNA.
RNA polymerase moves along DNA, unwinding the double helix and synthesizing a primary mRNA transcript by complementary base pairing.
State the base pairing rule between the DNA template and the primary transcript.
RNA polymerase synthesizes the primary mRNA transcript by complementary base pairing with the DNA template.
Compare exons and introns.
Exons are the coding regions retained, while introns are the non-coding regions removed during RNA splicing.
State the location of RNA splicing within a cell.
Nucleus
Describe the process of RNA splicing.
RNA splicing forms a mature mRNA transcript by removing non-coding introns and joining the coding exons.
State the location of translation within a cell.
Cytoplasm
Name the type of codon which begins translation and the type of codon which ends translation.
Translation begins at a start codon and ends at a stop codon.
Describe how the genetic code is translated into a sequence of amino acids.
Anticodons on tRNA bond to codons on mRNA, translating the genetic code into a sequence of amino acids.
Name the type of bond which forms between adjacent amino acids.
Peptide Bonds
Name the molecule produced following translation.
Polypeptide chain (protein)
Explain how different proteins can be expressed from one gene from alternative RNA splicing.
Different mature mRNA transcripts can be produced from the same primary transcript, allowing for the expression of different proteins from a single gene.
Explain why proteins have a three-dimensional shape.
The shape determines its function
Explain how phenotype is determined.
Phenotype is determined by the proteins produced from gene expression, influenced by both genetic and environmental factors.
Describe what is meant by a genetic mutation.
Mutations are changes in DNA that can result in no protein or an altered protein.
Describe the possible alterations to DNA nucleotide sequences that could result in a single gene mutation.
Single gene mutations involve substitution, insertion, or deletion of DNA nucleotides.
Compare missense, nonsense and splice site mutations.
Missense change one amino acid,
nonsense produce a premature stop codon,
and splice site affect inclusion of exons/introns in mRNA.
Describe the possible alterations to DNA nucleotide sequences that could result in a frame shift mutation.
Nucleotide insertions or deletions cause frame-shift mutations, changing all codons and amino acids after the mutation.
Explain why chromosome structure mutations are often lethal.
The chromosome structure is altered
Describe the following chromosome structure mutations- duplication, deletion, inversion and translocation.
Mutations include duplication (addition),
deletion (removal),
inversion (reversal),
and translocation (addition to non-homologous chromosome) of chromosome sections
State the term used to describe an organism’s entire hereditary information encoded in their DNA.
A Genome
Describe the makeup of an organism’s genome.
A genome consists of genes that code and other non-coding DNA sequence
Describe the purpose of bioinformatics.
Bioinformatics uses analyses to identify gene and amino acid sequences from genomic data.
Explain how the analysis of an individual’s genome can lead to personalised medicine.
An individual’s genome sequence can guide selection of effective drugs and dosage for their disease.
Describe metabolic pathways found within cells.
Metabolic pathways are integrated, enzyme-catalyzed reactions with reversible, irreversible, and alternative steps.
Compare anabolic and catabolic reactions.
“Anabolic reactions build large molecules from small ones and require energy,
while
catabolic reactions break down large molecules and release energy.”
Describe how metabolic pathways are controlled and their rate regulated.
They are controlled by the presence/absence of enzymes, and their rate is regulated by key enzyme activity.
Describe the role of the active site during an enzyme-controlled reaction.
it orientates substrate molecules so they fit more closely
Compare the affinity of the substrate and the product for the active site.
The substrate has high affinity, while the product has low affinity, allowing it to leave the active site.
Describe what happens during induced fit.
Induced fit is when the active site changes shape to better fit the substrate, lowering activation energy and temperature.
Explain why the rate of reaction increases then stays the same as the substrate concentration increases.
there are no more active sites available therefore no effect on rate of reaction
- Describe the changes to the rate and direction of metabolic pathway when the product concentration increases/decreases.
“High product concentration decreases rate and drives the pathway in reverse,
while
low product concentration increases rate and drives the pathway forward.”
Compare competitive and non-competitive enzyme inhibitors.
“Competitive inhibitors bind the active site, and can be reversed by increasing the substrate concentration
while
Non-competitive inhibitors bind elsewhere and change the active site shape. and CAN NOT be reversed”
Identify a type of inhibitor from a graph.
From the graph, a competitive inhibitor can be identified as its effect is reversible by increasing substrate.
Describe what happens during end product inhibition.
In end product inhibition, the final product inhibits an earlier enzyme, blocking the pathway and preventing further synthesis.
Describe the role of ATP in the transfer of energy.
ATP transfers energy to cellular processes requiring energy.
Describe the role of ATP in the phosphorylation of molecules.
ATP phosphorylates glucose and intermediates during glycolysis.
Name the part of the cell where glycolysis occurs.
Cytoplasm
Describe the process of glycolysis.
Glycolysis breaks down glucose to pyruvate.
Describe what happens to pyruvate in aerobic conditions.
pyruvate forms acetyl coenzyme A.
Name the part of the mitochondria where the citric acid cycle occurs.
Matrix of mitochondria
Describe the citric acid cycle.
The citric acid cycle converts acetyl groups to oxaloacetate, generating ATP and CO2.
Describe the role of dehydrogenase enzymes during glycolysis and the citric acid cycle.
Dehydrogenases remove H+ and e- to form NADH in glycolysis and the citric acid cycle.
Name the coenzyme which passes hydrogen ions and electrons to the electron transport chain.
NAD passes H+ and e- to the electron transport chain.
Name the part of the mitochondria where the electron transport chain occurs.
Inner Mitochondrial Membrane
Describe the electron transport chain
The electron transport chain pumps H+ across the membrane to drive ATP synthesis.
Describe what happens in muscle cells during vigorous exercise.
Describe what happens in muscle cells during vigorous exercise.
Explain how lactate can be converted back to pyruvate.
After exercise, the oxygen debt is repaid, allowing the liver to convert lactate back to pyruvate and glucose.
Name the organ which converts lactate to pyruvate.
The liver
Compare slow and fast twitch muscle fibres.
=- Slow: contract slowly but sustain contraction for longer,
Whereas
Fast: contract quickly but sustain for shorter.
- Slow: is useful for endurance activities such as long distance or cycling, Whereas Fast: such as sprinting or weightlifting
- Slow : have many mitochondria , high blood supply and high concentration of myoglobin ,Whereas,
Fast: have few mitochondria and low blood supply - Slow : rely in aerobic respiration
Whereas,
Fast: rely on glycolysis - Slow: major storage fuel is fat
Whereas Fast : major storage fuel is glycogen
